Cell-based therapies are rapidly gaining acceptance for use in treating a variety of diseases. The development of labeled materials to non-radioactively track therapeutic cells in vivo is needed to measure the efficacy of delivery, bio-distribution and effective dose. This new material(s) is designated "In Vivo Survey Technology" (IVST). IVST is a single tracer material designed to be assayed by a number of measurement technologies and designed to be readily taken up by cell populations in vitro. Assay technologies potentially useful for IVST measurements include neutron activation analysis for quantification, and optical fluorescence, x-ray fluorescence, electron microscopy and magnetic resonance for imaging. Since each technology offers distinct advantages to the researcher in tracking and quantifying cells in vivo, this project's major aim is to develop and test materials that can be detected and/or measured by all these technologies. In Phase I, materials will be tested to optimize for neutron activation analysis and at least two imaging technologies. The Phase II portion of this proposal will focus on tracking labeled cells in animal models to prove that all measurements can be performed with the newly developed IVST material(s) and to develop a variety of coatings that can either target IVST materials to specific cell types or be optimized for uptake into all cells. IVST will be used initially by scientists to determine the quantity and location of cells, such as stem cells, transplanted during pre-clinical research. IVST will allow researchers to conduct analyses on cell therapy not readily feasible previously. [unreadable] [unreadable]